Simulating galactic cosmic ray effects: synergy modeling of murine tumor prevalence after exposure to two one-ion beams in rapid sequence

Publication date: Available online 7 January 2020Source: Life Sciences in Space ResearchAuthor(s): Edward Greg Huang, Ren-Yi Wang, Liyang Xie, Polly Chang, Gracie Yao, Borong Zhang, Dae WoongHam, Yimin Lin, Eleanor Blakely, Rainer SachsABSTRACTHealth risks from galactic cosmic rays (GCR) in space travel above low earth orbit remain a concern. For many years accelerator experiments investigating space radiation induced prevalence of murine Harderian gland (HG) tumorigenesis have been performed to help estimate GCR risks. Most studies used acute, relatively low fluence, exposures. Results on a broad spectrum of individual ions and linear energy transfers (LETs) have become available. However, in space, the crew are exposed simultaneously to many different GCR. Recent upgrades at the Brookhaven NASA space radiation laboratory (NSRL) now allow mixtures in the form of different one-ion beams delivered in rapid sequence. This paper uses the results of three two-ion mixture experiments to illustrate conceptual, mathematical, computational, and statistical aspects of synergy analyses and also acts as an interim report on the mixture experiments' results. The results were interpreted using the following: (a) accumulated data from HG one-ion accelerator experiments; (b) incremental effect additivity synergy theory rather than simple effect additivity synergy theory; (c) parsimonious models for one-ion dose-effect-relations; and (d), computer-implemented numerical methods encapsulated i...
Source: Life Sciences in Space Research - Category: Biology Source Type: research